1. Field of the Invention
The present invention relates generally to medical devices which are used to provide access into the human body. More particularly, the present invention is directed to access devices which provide a single, relatively long-term, entry port into the body. The entry port is used by doctors and other medical professionals to selectively introduce a variety of medical implements and fluids into the body and for in vivo diagnostic testing and other treatment protocols.
2. Description of Related Art
A wide variety of medical devices have been developed in recent years for providing access into the human blood stream. These devices have traditionally been divided into two different groups based on their function and purpose. The first group of devices includes catheters which are designed to introduce therapeutic and/or diagnostic fluids into the blood stream. The second group includes devices commonly referred to as xe2x80x9cintroducersxe2x80x9d which are designed to provide an intermediate term access port into the body through which various medical implements may be passed for therapeutic and/or diagnostic purposes. As a generalization, catheters are longer and more flexible than introducers.
Central venous catheters are relatively long tubular devices which have tapered distal tips which are designed for entry into central veins to provide a dedicated route of fluid infusion into the body. The original venous catheters were single lumen devices which provided the ability to infuse a single liquid into the vein at one time. Multiple lumen catheters have since been developed which allow simultaneous introduction of two or more liquids into the vein. The central venous pressure catheter is a type of common multiple lumen catheter which allows the simultaneous introduction and withdrawal of fluids as well as the capability of monitoring blood pressure and other vital parameters. The portion of the catheter which remains outside of the body has been continually refined and redesigned to provide a low profile which increases comfort and reduces the awkwardness associated with a dedicated tube exiting the body.
Introducers are substantially different from catheters in both design and purpose. An introducer is an access device which is intended to provide a dedicated access port into the body. Catheters, on the other hand, are intended to be used to infuse or withdraw fluids from the body. Introducers typically include a relatively short lumen through which various medical implements, including catheters, can be selectively introduced and removed from the body. An important feature of any introducer is the valve assembly. The valve assembly provides a constant seal between the blood stream and the in vitro environment as medical implements are introduced and withdrawn from the body. The valve assembly is typically located outside of the body at the proximal end of the introducer. As a result, the proximal end of introducers has tended to be relatively bulky.
In addition to a valve assembly, many introducers include a side arm at the proximal end. The side arm is connected to the lumen so that fluids can be introduced into the body simultaneously with the medical device. The introducer lumen is considered to be a xe2x80x9csharedxe2x80x9d lumen in that the lumen provides a common conduit for both medical implements and fluid pharmaceuticals or diagnostics.
The currently available introducers and other access devices are well-suited for their intended purpose. However, new medical treatments and diagnostic procedures are continually being developed which require more versatile access into the body. For example, organ transplant procedures and cardiac angioplasty require the introduction of complex combinations of medical implements and diagnostic/therapeutic fluids into the body. Many of the presently available access devices are not well-suited for these relatively complex procedures. As a result, multiple access devices are required which must be located at multiple access sites necessitating multiple entry punctures. Accordingly, there is a continuing need to provide improved access devices that have additional capabilities which increase their versatility and usefulness for the increasing variety of invasive treatments and procedures.
In accordance with the present invention, an improved access device is provided which is designed to provide selective introduction of medical implements into the body while simultaneously providing auxiliary access through dedicated multiple lumens. The present invention is an improvement over existing introducers and other access devices in that multiple lumen access is provided through the introducer in addition to the shared lumen which is used for both medical implements and fluid pharmaceuticals or diagnostics. As an advantage, the improved access device reduces the number of devices required to introduce multiple implements and fluids into the body during complex surgical and diagnostic procedures.
The present invention desirably includes a multiple lumen access system for use in providing an entry port into the human body for selectively introducing medical implements therethrough and for providing simultaneous auxiliary access into the body. The system includes a multiple lumen access device comprising an outer tube which has a distal end for introduction into the body and a cross-sectional area. A device lumen through which medical implements may be passed is defined within the cross-sectional area of the outer tube, the device lumen having a distal end and a proximal end. At least one auxiliary lumen is defined within the cross-sectional area and separately from the device lumen, the auxiliary lumen having a distal end and proximal end. Finally, a device lumen valve is associated with the proximal end of the device lumen to provide sealing of the device lumen when medical implements are both present and absent from the device lumen. Such device lumen valve may be separate and detachable or it may be integral with the system.
A multiple lumen access system according to the present invention may also include a junction housing having a proximal end and a distal end to which the proximal end of the outer tube connects. The junction housing includes a main channel in fluid communication with the device lumen and at least one auxiliary channel in fluid communication with the at least one auxiliary lumen, the main channel and auxiliary channel(s) diverging from the outer tube to be non-intersecting in the junction housing.
In one embodiment, the device lumen valve is provided as a part of the junction housing and is in fluid communication with the main channel. A device channel may be formed in the junction housing at an angle with the main channel and terminating at an internal end in fluid communication with the main channel. The device lumen valve may be positioned at an external end of the device channel so that medical devices may be inserted therethrough and enter the main channel at an angle. The main channel desirably may continue from the distal end of the junction housing past the device lumen to an opening in the junction housing enabling introduction of fluids therethrough to the main channel. In one embodiment, the device lumen valve is molded separately from the junction housing of a material more rigid than the junction housing and is assembled with the multiple lumen access device by insertion in a cavity formed in the junction housing.
In an alternative embodiment, the main channel and auxiliary channel(s) of the junction housing may be oriented substantially coplanar so that the junction housing is substantially flat, the system further including an extension tube extending from the proximal end of the junction housing and in fluid communication with the main channel wherein the device lumen valve is connected to the extension tube to therefore be in fluid communication with the main channel. A side port in the device lumen valve may be provided enabling infusion of fluids to the extension tube and main channel. Furthermore, mating threaded connectors may be included between the device lumen valve and the extension tube enabling easy removal of the device lumen valve. Any appropriate connector, for example a luer connector, may be provided on the device lumen valve, and the system may also include an infusion syringe having a mating luer connector.
Further, in one embodiment, a multiple lumen access device may be provided with a multi-lumen sheath, a junction housing coupled to the multi-lumen sheath and a strain relief insert coupled to the junction housing. The strain relief insert is formed of a soft bendable material capable of flexing to prevent multi-lumen sheath from kinking at the sheath/junction housing coupling. In further embodiment, the multiple lumen access device is formed by coupling a single lumen catheter to a junction housing having a main channel and at least one auxiliary channel through a multi-function adapter.
In another embodiment, the present invention is directed to a multiple lumen access device including an outer tube which has a distal end for introduction into the body and a proximal end which remains outside of the body. The outer tube may have an exterior surface and an interior surface, the interior surface defining an access passageway which has a cross-sectional area which may vary at different locations between the distal and proximal ends of the outer tube. One or more inner walls are located within the access passageway. The inner wall may form an inner tube that surrounds a device lumen through which medical implements may be inserted into the body. At least one auxiliary lumen is located between the exterior surface of the inner wall and the interior surface of the outer tube.
As another feature of the present invention, two or more auxiliary passageways defined by the interior surface of the outer tube and the exterior surface of the inner walls. The provision of two or more auxiliary passageways allows introduction of additional diagnostics or pharmaceutical liquids simultaneously with introduction of a medical implement through the device lumen. Embodiments of the present invention are also described wherein a single auxiliary lumen is provided.
As a further desirable feature of the present invention the inner walls are sufficiently flexible to be movable from a relaxed position to expanded or contracted positions. The device lumen has a first cross-sectional area in the relaxed position, and in the expanded or contracted positions has cross-sectional areas which are greater than or less than the first cross-sectional area, and less than the cross-sectional area of the access passageway. The flexibility of the inner walls is advantageous in that it allows the insertion of a variety of medical implements having different cross-sectional areas. This flexibility allows the cross-sectional areas and resultant potential fluid flow rate for the auxiliary lumens and the device lumen to be controlled as desired and maximized within the confines of the access passageway.
As an additional feature of the present invention, spacer ribs are provided, for example, on the interior surface of the outer tube. The spacer ribs are located within the auxiliary lumens to prevent complete closure of the lumens during insertion of relatively large medical implements into the device lumen. The spacer ribs located on the surface of the inner wall insure that there is a passageway around devices located within the device lumen.
An alternative multiple lumen access device of the present invention comprises a tubular single lumen sheath having at least one infusion port and an elongated implement sized to fit coaxially within the single lumen sheath and form multiple independent lumens, and when at least one of the lumens is in fluid communication with the infusion port. The elongated implement may be formed from a sufficiently flexible material so that at least one lumen formed by the sheath and the implement has flexible walls movable from a relaxed to a flexed positions. Another alternative multiple lumen access device comprises a multi-lumen catheter having a main lumen tube, at least one side lumen tube connected in a side-by-side fashion with the main lumen tube and being peelable from the main lumen to form sidearms, and a hub connected to the main lumen tube and side lumen tube for fluid delivery or passage of a medical device therethrough.
The present invention is also directed to a method for introducing medical devices into the body through a single entry port while allowing simultaneous introduction of other devices, implements or fluids through the use of the multiple lumen access device of the present invention. In one embodiment, the method includes the steps of providing a multiple lumen access device in accordance with the present invention having at least one flexible wall; introducing the multiple lumen access device into the body with the distal ends of the device lumen and the auxiliary lumen being positioned within a vasculature of the body; and flowing a medical solution through the auxiliary lumen to move the flexible wall from the relaxed position to a flexed position.
In another embodiment, the method includes the steps of providing a tubular single lumen sheath having proximal and distal ends, at least one infusion port being provided on the proximal end of the sheath; providing an elongated implement sized to fit coaxially within the single lumen sheath, at least one of the lumens being in fluid communication with the infusion port; inserting the elongated implement into the single lumen sheath to form multiple independent lumens therein; and flowing a medical solution through one or more of the multiple independent lumens.
The above-described and many other features and attendant advantages of the present invention will become better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings.